Why is it called "Indian Summer"?

Here in the UK I thought it came from the days of the British Raj in India but it seems that is not correct.

Because the white men thought the Indians were gone because the weather was cold. But when the warm weather returned, so did the Indians.
Unlike the boys of summer. They leave as soon as summer is over.

Without googling, I don’t know how it actually came about, but it reminds me that I almost always have a positive feeling regarding sayings that use “Indian.” I know some people take offense to the usage, and that does matter to me, especially if the group themselves take offense.

Indian summer means to me a warm few days after the cold had already seemed to settle in as winter approaches. I always loved having a warm few days in November, a little reprieve from the cold.

Since you seem to be looking for some creativity—in my mind I think maybe it could have developed from Indians using dances or rituals to call on a break from the harshness of the cold. Or, maybe the Europeans who settled the northeast and mid Atlantic related this fluctuation in temperature during late fall as something that pertains to the new world, the Indian lands.

I too am curious, so I looked it up:

“During the beginning of the 19th Century, the American phrase “Indian Summer” became better known. Although the exact origins of the term are uncertain, it is thought to have been based on the warm and hazy conditions in autumn when native American Indians chose to hunt.”

Source: What is the source of ’‘Indian Summer’’ and is it offensive?

The Brits use the term as well, as noted by @flutherother above, and the term may very well have a different origin across the water.

I’ve never researched the term at all, but I’ve grown up in New England and experienced it every year, of course. I presumed that it was faintly pejorative in the same way that “Indian giver” is a term that is strictly pejorative.

Most of us (at least in the States) know of the term “Indian giver” as someone who offers a gift and then takes it back. (And no, I don’t know the exact origin of that term, either, except that I think it has to do with the way that European settlers and Native Americans looked at the issue of “property” and “land ownership” through very different cultural lenses.)

So in that sense, “Indian summer” is a way of “taking back” the summer season again, after the first frost seems to have signaled the end of the season.

I agree with @CWOTUS. I also thought it related to the same premise as ‘Indian Giver’. An Indian summer is too early. A false summer. It is there and then taken away again.

I understand that the phrase came into use in early Colonial times, when an unusual period of fairly warm weather in late fall or winter, would usually bring out Indian raiding parties. Hence the term, “Indian Summer”.

I don’t relate it to Indian giver at all. I do agree the expression Indian Giver is offensive, even though I never thought of Indians as being “indian Givers” when I used to use it. Indian giver was a misunderstanding between cultures. I also used to sit Indian style and sing one little two little three little Indians. I assume they don’t sing that anymore.

@Earthbound_Misfit I don’t think of Indian Summer as too early. It’s usually at the beginning of the cold season not anywhere near the beginning of spring let alone summer. Maybe in your hemisphere it is used as spring approaches?

I always thought it meant hot.

@AshlynM It does mean a hot spell in Fall but the question is about nomenclature.